Intermittent inductive train control system



April 1932- w. K. HOWE INTERMITTENT INDUCTIVE TRAIN CONTROL SYSTEM FiledAug. 17 1925 lqll l hl l l M I I M M tmv TOR BY (J W ,g A TToRNEYPatented Apr. 5, 1932 UNITED STATES PATENT oFFicE.

WINTHROP K. HOWE, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAYSIGNAL COMPANY, OF ROCHESTER, NEW YORK INTERMITTENT INDUC'IIVE TRAINCONTROL SYSTEM Application filed August 17, 1925.

This invention relates to automatic train control systems for railroads,and more particularly to systems of the intermittent impulse type, andto the control of the impulse transmitting track devices and associatedtrackway block signals.

In one type of train control system, to which the present invention moreparticularly relates, the engineer is required to perform w an act,commonly termed acknowledgement, in recognition of each caution or stopsignal, otherwise an automatic application of the brakes occurs and apenalty is imposed. In such a system, the engineer determines from 5 theindications of the trackway block signals whether or not it is necessaryfor him to perform an acknowledging act.

The trackway impulse device of an intermittent system, to conform withthe principle 29 of failure on the side of safety, is ordinarilyprovided with a control circuit, which must be closed, either with orwithout current flow, to render the trackway impulse device ineffective.

It is desirable that the controlling condition of the trackway impulsedevice, and the indication of the associated trackway block signaling,should correspond at all times, even in the case of some defect orfailure. The signal should not give a favorable indication of proceed.if the trackway impulse device is in fact in its active stoppingcondition, otherwise a brake application will occur through no fault ofthe engineer, not only producing an unnecessary brake application, buttending to weaken the engineers confidence in the reliability of thesystem. Thus, if the trackway device can not assume its inactive ornon-stopping condition, due to some defect. the trackway signal shouldbe prevented from indicating proceed, even though traffic conditionsahead justify such an indication. Furthermore, it is consideredpreferable for the trackway impulse device to be in its active stoppingcondition, if the trackway signal indicates caution or stop, due to somedefect in such signal, even though the trafiic conditions are in factsafe.

With these and other considerations in mind, it is proposed inaccordance with the Serial No. 50,685.

present invention to provide an organization of parts and circuits suchthat the trackway signal can not give a favorable indication, unless thecontrol circuit for the trackway impulse device is at that time Intactand capable of rendering said device inactive, and also so that thecontrolling condition of the trackway impulse device is dependent uponthe position orindication of the trackway signal, independently of itscontrol from the trackway.

Other specific objects, advantages and characteristics of the inventionwill be in part apparent, and in part pointed out hereinafter.

The accompanying drawing illustrates in a simplified and diagrammaticmanner one specific embodiment of the invention applied to one signallocation, the trackway signal being of the semaphore type, and thetrackway impulse device ofthe inert element type.

To illustrate and explain the nature of the invention I have shown itsapplication to one signal location on a double track railroad in whichtraflic normally moves in one direction, as indicated by the arrow. Itshould be understood, however, that the invention is applicable tosingle track railroads, equipped with a block signaling system of thetype commonly known as an absolutepermissive-block type or the typicalsingle track signaling system, as will be evident when thecharacteristic features of the invention are understood. The track rails1 of the railroad track are divided by insulated joints 2 into tracksections, one or more sections constituting the usual block, inaccordance with common and recognized practice. Each of these tracksections is provided with a track battery 3, or equivalent source ofcurrent, and a track relay T, providing the usual and well knownnormally closed track circuit.

While the invention is applicable to trackway signals of Various types,a semaphore signal Z of the three-position type has been shownconventionally; and as shown, the control circuits for this signal areof the well known typical form, using a home relay H and a distant relayD. The front contact 4 of the home relay H controls the usual 45 degreecontrol circuit for the signal Z, which causes it to move from itshorizontal or zero degree position to its inclined or 45 degree positionto give a caution indication; and the front contact 5 of the distantrelay D controls the usual degree control circuit to move the semaphorefrom its inclined or 45 degree to its vertical or 90 degree position andgive the proceed or clear indication. To carry out this invention, theenergizing circuits for the home and distant relays H and D differ fromthose commonly used in a particular manner which is more convenientlypointed out hereinafter in connection with the description of theoperation.

The signal Z is provided with a circuit controller of the usual wellknown construction, which is shown in accordance with establishedconvention. This circuit controller includes contacts 9, which areprovided specially to carry out this invention and which are closed, asindicated by the conventional showing, only if the semaphore is in itsvertical or proceed position.

When the invention is applied to a light signal, the function of thesecontacts 9 may be obtained by a front contact of the relay giving whenenergized the clear or proceed indication of the signal, or by thecontacts of a relay connected in series with the filament of the lamp orlamps giving the clear indication, or otherwise associated with saidfilaments, so that said contacts are closed only if the signal is givinga clear indication. Such adaptations, being obvious to those skilled inthe art are not illustrated.

Associated with the signal Z is the trackway impulse device TD of atrain control system of a type which makes the application of thisinvention desirable. For the purpose of illustration, this trackwayimpulse device TD is assumed to be of the inert element type, comprisinga coil 10 on a non-magnetized iron core 11, ordinarily U-shaped andprovided with enlarged pole pieces. It is contemplated that thistrackway impulse device TD will cooperate with a suitable car-carriedreceiver, together with brake control apparatus 0n the car, to producean automatic brake application at each caution or stop signal, unlessthe engineer operates an acknowledging device. Such a system isdisclosed, for example, in my prior Patent No. 1,604,098, dated October19. 1926.

This track way impulse device TD is in its active stopping condition,and transmits an impulse to a passing train when its coil 10 is on opencircuit. and is in itsinactive or non-stopping condition, when its coil10 is included in a closed de-energized circuit of preferably lowresistance or impedance. It should be understood that the circuitincluding the coil 10 of the trackway device TD must not only be closed,but must also be of relatively low resistance or impedance, in orderthat said trackway device may not influence the receiver on a passingtrain and produce a stopping impulse. It is therefore proposed inaccordance with the present invention to provide means whereby beforethe wayside signal can be cleared the coil 10 must at least be intact tocomplete a circuit of rather high impedance and which impedance is toohigh to render the trackway device TD inactive, and whereby if thewayside signal is in proper working order and assumes the proceed orclear position through such ircuit of high impedance the impedance ofthis circuit including coil 10 is then reduced. In other words, it isproposed to prevent clearing of the wayside signal unless the coil 10 isintact and to prevent placing the coil 10 in a circuit of low resistanceunless the wayside signal assumes the clear position.

In order to accomplish this end there is connected in multiple with thecircuit con troller 9 current limiting device 12, which is so selectedand proportionet that, when included in the closed circuit for the coil10 of the trackway device TD, it will still render said trackway deviceactive. This current limiting device 12 is preferably an impedance,usually including an iron core, having a coil thereon of relatively lowohmic resistance, although this, and other characteristics of the device12, are'optional and susceptible of modification in practice.

O7)erati0n.Normally, under clear trailic conditions ahead, the homerelay H is energized from a battery 31, or other source of current, inadvance, over a line wire 13 including the front contacts 1% and 14 ofthe track relays T and T of the track sections constituting the blockbetween the signal Z and the next signal in advance, wire 15, relay H,wire 16, contact finger 17 and its front contact of relay D, wires 18,19 and 20 to the common return wire C and thence back to said source ofcurrent in advance. In practice, this line circuit for the relay H wouldalso include any other controls governing the stopping condition of thesignal Z, as for example, the front contact of the relay ll of thesignal next in advance, in an A. P. B. system.

Under normal conditions, with the signal Z in its clear position andcontacts 9 of its circuit controller closed, and the wires of thecontrol circuit of the coil 10 of the trackway impulse device TD intact,there is a shunt or multiple path around the front contact 17 of therelay D, through which part of the energizing current for the home relaymay flow. this shunt starting at the heel of the contact finger 17,being as follows: wire 21., contacts 9, wire 22, coil 10, wires 23 and18. On account of the relatively high resistance of the coil 10 ascompared with the resistance of contacts 17 and wire 18, a very smallpart Liu of the energizing current for the home relay H will normallyflow through this shunt.

Under normal conditions, the distant relay D is energized from a battery31, or other source of current, in advance, over a line circuit,including wire 24:, and controlling contacts 32 which govern the proceedor clear indication of the advance signal Z, the circuit proceedingthrough line Wire 24. through the finger and front contact 25 of thehome relay H, wire 26, relay D, wire 27, finger 17 and front contact ofrelay D, wires 18, 19 and 20, to the common return wire C, and thenceback to said battery- In one typical arrangement, which may be assumedfor the purposes of this case, the line circuit for energizing thedistant relay D or signal Z is taken through a circuit controller 32"011 the signal next in advance closed when said signal next in advanceis in its caution or proceed position.

Under the normal conditions described, coil 10 of the trackway impulsedevice TD is in eluded in a closed circuit of relatively low ohmicresistance as follows :commencing at the coil 10, Wire 22, contacts 9,wire 21, finger 17 and its front contact of relay D, and wire 18 and 23.The device TD is thus rendered inactive.

If, under ectain conditions, the signal Z should happen to assume itscaution or stop position, even though there were no train in advance, onaccount of some defect, such as breaking of a control wire, then thecontacts 9 of the circuit controller of the signal Z would open andinclude the current limiting device 12 in the circuit for the coil 10 ofthe device TD, thus rendering this device TD active to stop the train byreason of the fact t. at the choking effect of coil 10 has beensubstantially killed or subdued.

To bring out other characteristic features of the invention, assumingthat a train passes the signal Z, let us consider the controllingcondition of the trackway impulse device TD and the indication of thesignal Z under various conditions, including defects in the controlcircun for said device TD, and in the signal operating mechanism.

When the train enters the track section J and de-energizes the trackrelay T, its finger 14cand front contact opens the energizing circuitfor the home relay H; and the finger 25 and front contact of said homerelay H in turn open the energizing circuit for the distant relay D, sothat both of the relays H and D are de-energized. The de-energization ofthe relay D opens the control circuit for the coil 10 of the trackwaydevice TD at the finger and front contact 17, so that said trackwaydevice TD assumes its active stopping condition. It snould be noted thatthis will occur, even though the signal Z should,

, for any reason, remain in its clear position;

and in the event the signal does stick clear upon de-energization ofrelay D the controlling condition of the trackway device TD and theindication of the signal Z do not correspond. It is considered to bemore important, however, to have the trackway device TD in the stoppingcondition, when the preschanically stuck in the clear position and it isobvious that an automatic brake application should occur in such rareinstances, even though the engineer may be penalized for no fault of hisown.

As the train advances out of the block protected by the signal Z, sothat the contacts, such as the front contact 14 of the track relay T,included in the energizing circuit for the home relay H, are all closed,and the signal Z may properly assume its caution position,

so far as traflic conditions are concerned, said home relay H becomesenergized, providing the control circuit for the coil 10 is intact.Since the distant relay D is de-energized, the energizing current forthe relay H must pass over wire 21, through the current limiting device12, wire 22, through the coil 10 and through wire 23. If, due to thepassage of the train, or any other cause, the wires of the coil 10, ortheir connections, are broken, so that the trackway device D could notbe placed in its inactive or non-stopping condition, then the home relayH cannot be energized, and the signal Z remains in the stop position. Inother words, the integrity and continuity of the control circuit for thetrack device TD is checked each time the signal Z goes to stop; and ifanything is wrong with this control circuit, this signal remains in thestop position. In this way, the indication of the signal Z is made tocorrespond with the controlling condition of the track device TD; andwhen this track device cannot assume its inactive condition, due to somedefect, the indication of the signal warns the engineers of passingtrains to acknowledge.

Even though the control circuit for the coil 10 of the trackway deviceTD is intact, and the home relay H may be energized to move the signal Zto the caution position, nevertheless said trackway device TD remainsactive, because the contacts 1'? are open and the cur rent limitingdevice 12 is included in its control circuit.

After the passing train has advanced to the point where the distantrelay D may be properly energized to L llow the signal Z to assume itsproceed or clear position (beyond the exit end of block K in thearrangement shown in the drawing), this relay D is energized, providingthe control circuit for coil 10 is still intact, the energizing currentfor the relay D being obliged topass through the coil 10 and its controlwires, the same as in the case of the home relay H. When the distantrelay D is energized and its front contacts 17 closed, the track deviceTD assumes its inactive or non-stopping condition, providing the signalZ also moves to the 90 degree or proceed position and closes itscontacts 9 to shunt the current limiting device 12. If the signal Zshould for any reason fail to assume its clear position, the trackwaydevice TD is maintained in its active stopping condition.

This feature, just described, which prevents the track device TDassuming the inactive condition unless the signal Z actually indicatesproceed, is of particular advantage in the type of permissive systemsuch as disclosed, for example, in the patentto Chas. S. Bushnell, No.1,686,434 dated October 2, 1928, in which the engineer is given anindication in the cab, usually audible, whenever he op crates hisacknowledging device, to tell him when he may properly restore theacknowledging device to normal. In this type of system, if the engineermaintains his acknowledging device in the operated position longer thana predetermined time, such as fifteen seconds, the brakes areautomatically applied; and the audible signal is helpful to the engineerby advising him at the earliest moment when he may properly release hisacknowledging device. Now, with such a system wherein the features ofthis invention are not present, if the signal should, due to the somedefect, indicate caution, even though the track ahead were clear and thetrack device in its inactive or non-stopping condition, the engineerwould acknowledge, but no impulse being transmitted by the inactivetrack device, the audible signal would not be given, and the engineermight hold down his acknowledging device so long as to get a brakeapplication, while waiting for the audible signal to be given.

From the foregoing explanation, it can be seen that I have provided ameans of control for the wayside block signal and track impulsetransmitting device of an intermittent train control system, so as toobtain in a simple and direct way an efiective check on failure ofeither the signal or the trackway device to perform its intendedfunction. In addition to the features already pointed out, it will benoted that, if the trackway device TD should happen to be torn out by apassing train, the associated signal Z would remain in the stopposition. In this case, as well as in the others previously explained,all defects and failures at all likely to occur are on the side ofsafety; and in addition, the controlling condition of the trackwaydevice TD is made dependent upon the existing indication of the signalZ, so far as consistent with safety, so that the engineer may not bemisled by the indication of the signal Z and acknowledge, or fail toacknowledge, unless the track device TD is in corresponding condition.

Although I have shown and described in detail one specific embodiment ofmy invention, it should be understood that the specific means andcircuit connections shown and described are susceptible of modification,without departing from the invention.

What I claim is 1. In a train control and wayside signaling system, awayside signal, trackway impulse device for train control purposeshaving a control circuit, said trackway device assuming its activecondition unless said control circuit is closed, contacts in saidcontrol circuit associated with the wayside signal and closed only ifsaid signal indicates proceed, a relay controlled in accordance withtraffic conditions ahead for independently governing said controlcircuit, and a circuit for re-energizing said relay after oncede-energized including in part the wires of said control circuit.

2. In a train control and wayside signaling system, a wayside signal, atrackway impulse device for transmitting control influences inductivelythrough an air gap to passing vehicles, said trackway device including awinding and assuming its active stopping condition unless a controlcircuit through said winding is closed, a relay controlled in accordancewith traffic conditions ahead for governing the indication of thewayside signal, circuit controlling means associated with said signaland closed only if it indicates proceed, said control circuit for thetrackway impulse device including a front contact of said relay and saidcircuit controlling means in series, and a stick circuit for said relayincluding said front contact, whereby upon deenergization of said relay,it cannot be again energized except by current flowing in part throughthe control circuit for the trackway impulse device.

3. In a train control and wayside signaling system, a wayside signal,contacts associated with said signal and closed only if it indicatesproceed, a-trackway impulse device for transmitting control influencesto passing vehicles, said trackway device comprising an inert magneticcore and a coil thereon and assuming its active stopping conditionunless said coil is included in a closed circuit of low impedance, arelay governed in accordance with traflic conditions ahead, a stickcircuit for said relay including a front contact thereof,

a control circuit for said coil of the trackway device including saidcontacts of the signal and said front contact of the relay and a currentlimiting device connected in multiple with said contacts of the signal.

4. In a Wayside signal and train control system, a trackway impulsedevice having a control circuit and assuming its active stoppingcondition unless said control circuit is closed and is of relatively lowimpedance, a relay governing said signal, means determining theenergizati on of said relay depending upon the flow of the currentthrough. the control circuit of the trackway impulse device regardlessof whether the impedance of said control circuit is low or high, andmeans for automatically rendering the impedance of said control circuitrelatively high unless the wayside signal indicates proceed.

5. In a train control system of thecharacter described, in combinationwith a trackway impulse device comprising a coil, said trackway deviceassuming its active impulse transmitting condition unless said coil isincluded in a closed circuit of relatively loW impedance, means forgoverning said control circuit in accordance with traffic conditionsahead, a wayside signal, and means associated with said signal forchanging the impedance of said control circuit without interrupting itscontinuity dependent upon the indication of said signal.

6. In a train control system, the comb-ination with a wayside signal, ofa train control track device, a control circuit of said device acting ifclosed to render said device inactive, means having its operationdependent upon the continuity of said control circuit for governing theindication of the wayside signal, and means associated with said signaland acting upon said control circuit without interrupting its continuityto cause said trackway device to assume its active stopping conditionunless said wayside signal indicates proceed.

7. In a system of the character described, a train control trackwayimpulse device comprising an inert body of iron with a coil thereon,means governed in accordance with traffic conditions ahead for includingsaid coil in a closed circuit of low impedance, a wayside signal,contacts associated with said signal and closed only if it indicatesproceed, and an impedance connected in multiple with said contacts insaid control circuit.

8. Trackway equipment for a combined trackway signaling and traincontrol system comprising, a wayside signal, a trackway impulse devicehaving a magnetic core and a coil thereon, a relay governed inaccordance with traffic conditions ahead for controlling the indicationof said signal, an energizing circuit for said relay including said coilof the trackway device and an impedance in series, whereby said relaywhen once de-energized can not be again energized unless said coil isintact, and contacts closed only if said signal indicates proceed andconnected in multiple with said impedance.

9. A combined system of Wayside signaling and train control comprising,an impulse transmitting trackway element having an active and aninactive condition, a wayside signal, and automatic means for preventingsaid signal from giving a favorable indication, after having once beencontrolled to give a restrictive indication, unless said trackway deviceis capable of assuming its inactive condition, said means alsopreventing said track- Way device assuming such inactive conditionuniessthe wayside signal gives its favorable indication.

l0. The combination with a trackway im-V favorable indication.

11. In an automatic wayside signal and train control system; thecombination with a wayside signal; a traclrway train control devicewhich includes a control circuit which must be intact to permit saiddevice to be placed in its inactive non-stopping condition; a relaycontrolled in accordance with trailic conditions ahead; and means forcausing said signal to indicate proceed if said trackway train controldevice has its control circuit intact and said relay manifests favorabletraffic conditions ahead, and for causing said trackway train controldevice to assume its inactive non-stopping condition only if both saidsignal indicates proceed and said relay manifests favorable traficconditions ahead.

12. In an automatic wayside signal and train control system, thecombination with a wayside signal, a trackway train control device whichincludes a control circuit which must be intact to permit said device tobe placed in its inactive non-stopping condition; a relay controlled inaccordance with traffic conditions ahead, means requiring the integrityof said control circuit in order to function for causing said signal toassume the proceed condition in response to a favorable indicatingcondition of said relay, and means for placing said trackway device. inits inactive non-stopping condition only if both said signal and saidrelay indicate favorable traflic conditions.

13. The method of checking the proper functioning of a trackwayinfluence communicating device which if active restricts the progress ofthe train of a'train control system by a proper wayside signalindication of a railway signaling system on which the train controlsystem is superimposed and of checking the proper functioning of thewayside signal by placing the trackway device in a correspondingcondition, which consists in first detecting whether or not the trackwaydevice can be rendered inactive without actually rendering it inactive,then if said device is in condition to be rendered inactive allowingsaid wayside signal to clear providing traflic conditions ahead areclear, and then in rendering said trackway' device inactive in responseto clearing of said wayside signal.

In testimony whereof I aifix my signature.

WINTHROP K. HOWE.

